The corner of 15th and K streets in Washington, D.C., is busy. Buses, trucks, cars and taxis zip by. There are pedestrians and, increasingly, bikes.Some 57 million adults ride bicycles in the U.S., whether for commuting or exercise or fun.

With Mayor Rahm Emmanuel saying he’s committed to making the "City that Works" the most bike-friendly in the country, Chicago is experiencing a two-wheeled revolution. That’s music to Greg Borzo’s ears, author of Where to Bike: Chicago, a guide to Chicagoland’s best cycle routes.

If you’ve ever ventured out into one of Chicago’s famous six-corner intersections, you know the streets don’t always feel safe. The facts bear this out. In 2009 there were over 4,500 crashes between Chicago drivers and pedestrians or cyclists, 35 of which were fatal.

As passionate as many American cyclists are, biking in the United States is hardly as mainstream as it is in much of the world. In fact, in the U.S., home to Detroit and land of the pickup truck, only about 1% of trips are made by bicycle.But is cycling political?